DOCSLIB.ORG

Paul Langévin (1872 -- 1946)

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Paul Langévin (1872 -- 1946) Paul Langevin (1872 -- 1946) Paul Langevin was born in Paris on 23 January 1872. He attended the Ecole Lavoisier and the Ecole de Physique et de Chimie Industrielles, where he was supervised by Pierre Curie (1859-1906) during his laboratory classes. In 1891 he entered the Sorbonne, but his studies were interrupted for a year in 1893 by his military service. In 1894, Langevin entered the Ecole Normale Superieure, where he studied under Jean Perrin (1870-1942). Langevin joined the Collage de France in 1902, and was made Professor of Physics there in 1904, a post he held until 1909 when he was offered a similar position at the Sorbonne. Contemporary to Marie Curie, Albert Einstein and Hendrik Lorentz, he was noted for his work on the molecular structure of gases, analysis of secondary emission of X-rays from metals exposed to radiation and for his theory of magnetism. He suggested that the alignment of molecular moments in a paramagnetic substance would be random in the absence of an externally applied magnetic field, but would be non-random in its presence. The greater the temperature, however, the greater the thermal motion of the molecules and thus the greater the disturbance to their alignment by the magnetic field. Langevin further postulated that the magnetic properties of a substance are determined by the valence electrons, a suggestion which influenced Niels Bohr (I885-1962) in the construction of his classic model describing the structure of the atom. He was able to extend his description of magnetism in terms of electron theory to account for diamagnetism. He showed how a magnetic field would affect the motion of electrons in the molecules to produce a moment that is opposed to the field. This enabled predictions to be made concerning the temperature-independence of this phenomenon and furthermore to allow estimates to be made of the size of electron orbits. He published his work on the atomic theory of Para magnetism in 1905. In the same year Albert Einstein correctly identified Brownian motion (such motion, visible only under a microscope, is the incessant, random movement of micrometers-sized particles immersed in a liquid) as due to imbalances in the forces on a particle resulting from molecular impacts from the liquid. Shortly thereafter, Langevin formulated a theory in which the minute fluctuations in the position of the particle were due explicitly to a random force. Langevin's approach proved to have great utility in describing molecular fluctuations in other systems, including nonequilibrium thermodynamics. In the later years, Langevin became increasingly involved with the study of Einstein's work on space and time. He was a firm supporter of the theory of the equivalence of energy and mass. Einstein later wrote that Langevin had all the tools for the development of the special theory of relativity at his disposal before Einstein proposed it himself and that if he had not proposed the theory, Langevin would have done so. Langevin was responsible for some of the most important work on piezoelectricity and on piezoceramics for which he was generally remembered. He was the inventor of the underwater Sonar for submarine detection during World War I, where his theories and researches were extensively utilized by the French and the Americans. In 1916 he was able to obtain echoes from the bottom and from a sheet of metal at a distance of 200 meters. In 1917 Langevin started to use the piezoelectric effect, rather than the electrostatic projector and carbon-button microphone used in 1916. He also started the use of vacuum tube amplifiers in underwater sounding equipment, this is thought to be the first use of electronics in this manner. With this new technology echoes were received from a submarine for the first time, in 1918, as deep as 1500 meters. Their transducer was a mosaic of thin quartz crystals glued between two steel plates (the composite having a resonant frequency of about 50 KHz), mounted in a housing suitable for submersion. Working on past the end of the war, they did achieve their goal of emitting a high frequency "chirp" underwater and measuring depth by timing the return echo. The strategic importance of their achievement was not overlooked by any industrial nation, however, and since that time the development of sonar transducers, circuits, systems, and materials has never ceased. After world war I his echo sounding devices were employed in many French ocean-liners, starting with the Ile de France in 1928. He was soon arrested by the Nazis for his outspoken antifascist views. He was first imprisoned in Fresnes, and later placed under house arrest in Troyes. The execution of his son-in-law and the deportation of his daughter to Auschwitz (which she survived) forced Langévin to escape to Switzerland in 1944. He returned to Paris later that year and was restored to the Directorship of his old school, but died soon after, in Paris on 19 December 1946. The modern ultrasonics era arose from Professor Langevin's 1917 invention of the quartz sandwich transducer for underwater sound transmission in submarine detection. Intense ultrasound's physical effects had not gone unnoticed in the first decade of modern ultrasonics. Langevin's tests with quartz plate transducers had resulted in killing fish in the beam of sound. Professor Van Dyke had observed in 1924 the searing of skin when a resonant quartz bar was touched, the explosive atomization of water drops from the end of the rod and friction alleviation between a metal surface and the vibrating quartz. Nevertheless, no steps were taken to investigate these early observations more fully. Among observers of Langevin's work was Professor R. W. Wood, an American physicist from Johns Hopkins University. Already famous for his work in optics and spectroscopy, and for his classic book "Physical Optics," he was also known as a brilliant lecturer and a writer of popular fiction and verse. With U.S. entry into WW I, Professor Wood was commissioned an Army Major and assigned to the Bureau of Inventions in Paris, where he devoted particular attention to the work of Langevin. Wood later noted how the contact with Langevin had made a strong impression: "It was my good fortune during the war to be associated for a brief time with Prof. Langevin during his remarkable developments. At the arsenal at Toulon I witnessed many of the experiments with the high power generators. One was mounted in a large wooden tank filled with sea water, and when the Poulsen arc was started and the frequency adjusted for resonance the narrow beam of supersonic waves shot across the tank causing the formation of millions of minute air bubbles and killing small fish which occasionally swam into the beam. If the hand was held in the water near the plate an almost insupportable pain was felt, which gave one the impression that the bones were being heated." Another wartime meeting that proved essential to the invention of power ultrasonics occurred when Professor Wood met Alfred L. Loomis at the Aberdeen Proving Grounds. Loomis, a successful lawyer, was directing Aberdeen research as an Army Major and invented, during this time, the "Loomis chronograph" for measuring the velocities of shells. After the war, Wood pursued other areas of war research and returned to his work in optics and spectroscopy, with his interests in ultrasonics remained dormant for several years. Loomis, following the war, entered investment banking, amassing a personal fortune during the 1920s. However, his interest returned increasingly to scientific research and, in 1924, Loomis renewed the wartime acquaintance with Wood and offered to collaborate and underwrite any joint research ventures. In 1926, Wood told Loomis of Langevin's experiments and suggested the subject offered a wide field for research in physics, chemistry, and biology. With a high power General Electric vacuum-tube oscillator and a quartz plate transducer immersed in an oil- filled dish, experiments began in Loomis's garage in Tuxedo Park, New York. As research expanded, Loomis purchased a nearby mansion, converting it into his well-known Tuxedo Park Laboratory. The huge vacuum tubes, a large bank of oil condensers and an oversize variable condenser and step-up induction coil made the ultrasonic apparatus an imposing affair. Vibrations of 200-500 kHz were transmitted through the oil bath into glass vessels or rods immersed in the bath, achieving a range of spectacular effects that included: radiation pressures of sufficient magnitude to support 150 g and to raise a pronounced mound of oil above the transducer; intense searing of the skin by the vibrating glass rod and the burning of wood chips and the etching and drilling of glass pressed against the tips of vibrating glass rods; heating of liquids and solids and the formations of emulsions and fogs; biological effects including rupturing of red blood cells, killing of cellular organisms, and harmful to lethal effects on fish, frogs, and mice; observations of chemical reactions and crystallization and flocculation of particles suspended in a liquid. These pioneering results could be taken as a present-day litany of ultrasonic achievements. Wood and Loomis also made observations of the modal patterns of rods, tubes, and plates and gave some of the first experimental data on phase velocity in rods and disks. Another first occurred when they made an ultrasonic horn by drawing down a glass tube to a tapered point to concentrate the energy at the point of application. Publication of these results started avenues of work being exploited to the present day. Professor Wood did not continue work in ultrasonics, but returned to optics and spectroscopy. Aside from a 1939 "supersonics" monograph, in a scientific career spanning a half-century, this was to represent his involvement with ultrasonics.
Load more

Recommended publications
  • A Brief History of Nuclear Astrophysics
    A BRIEF HISTORY OF NUCLEAR ASTROPHYSICS PART I THE ENERGY OF THE SUN AND STARS Nikos Prantzos Institut d’Astrophysique de Paris Stellar Origin of Energy the Elements Nuclear Astrophysics Astronomy Nuclear Physics Thermodynamics: the energy of the Sun and the age of the Earth 1847 : Robert Julius von Mayer Sun heated by fall of meteors 1854 : Hermann von Helmholtz Gravitational energy of Kant’s contracting protosolar nebula of gas and dust turns into kinetic energy Timescale ~ EGrav/LSun ~ 30 My 1850s : William Thompson (Lord Kelvin) Sun heated at formation from meteorite fall, now « an incadescent liquid mass » cooling Age 10 – 100 My 1859: Charles Darwin Origin of species : Rate of erosion of the Weald valley is 1 inch/century or 22 miles wild (X 1100 feet high) in 300 My Such large Earth ages also required by geologists, like Charles Lyell A gaseous, contracting and heating Sun 푀⊙ Mean solar density : ~1.35 g/cc Sun liquid Incompressible = 4 3 푅 3 ⊙ 1870s: J. Homer Lane ; 1880s :August Ritter : Sun gaseous Compressible As it shrinks, it releases gravitational energy AND it gets hotter Earth Mayer – Kelvin - Helmholtz Helmholtz - Ritter A gaseous, contracting and heating Sun 푀⊙ Mean solar density : ~1.35 g/cc Sun liquid Incompressible = 4 3 푅 3 ⊙ 1870s: J. Homer Lane ; 1880s :August Ritter : Sun gaseous Compressible As it shrinks, it releases gravitational energy AND it gets hotter Earth Mayer – Kelvin - Helmholtz Helmholtz - Ritter A gaseous, contracting and heating Sun 푀⊙ Mean solar density : ~1.35 g/cc Sun liquid Incompressible = 4 3 푅 3 ⊙ 1870s: J.
    [Show full text]
  • ARIE SKLODOWSKA CURIE Opened up the Science of Radioactivity
    ARIE SKLODOWSKA CURIE opened up the science of radioactivity. She is best known as the discoverer of the radioactive elements polonium and radium and as the first person to win two Nobel prizes. For scientists and the public, her radium was a key to a basic change in our understanding of matter and energy. Her work not only influenced the development of fundamental science but also ushered in a new era in medical research and treatment. This file contains most of the text of the Web exhibit “Marie Curie and the Science of Radioactivity” at http://www.aip.org/history/curie/contents.htm. You must visit the Web exhibit to explore hyperlinks within the exhibit and to other exhibits. Material in this document is copyright © American Institute of Physics and Naomi Pasachoff and is based on the book Marie Curie and the Science of Radioactivity by Naomi Pasachoff, Oxford University Press, copyright © 1996 by Naomi Pasachoff. Site created 2000, revised May 2005 http://www.aip.org/history/curie/contents.htm Page 1 of 79 Table of Contents Polish Girlhood (1867-1891) 3 Nation and Family 3 The Floating University 6 The Governess 6 The Periodic Table of Elements 10 Dmitri Ivanovich Mendeleev (1834-1907) 10 Elements and Their Properties 10 Classifying the Elements 12 A Student in Paris (1891-1897) 13 Years of Study 13 Love and Marriage 15 Working Wife and Mother 18 Work and Family 20 Pierre Curie (1859-1906) 21 Radioactivity: The Unstable Nucleus and its Uses 23 Uses of Radioactivity 25 Radium and Radioactivity 26 On a New, Strongly Radio-active Substance
    [Show full text]
  • A Brief History of Mangnetism
    A Brief history of mangnetism Navinder Singh∗ and Arun M. Jayannavar∗∗ ∗Physical Research Laboratory, Ahmedabad, India, Pin: 380009. ∗∗ IOP, Bhubaneswar, India. ∗† Abstract In this article an overview of the historical development of the key ideas in the field of magnetism is presented. The presentation is semi-technical in nature.Starting by noting down important contribution of Greeks, William Gilbert, Coulomb, Poisson, Oersted, Ampere, Faraday, Maxwell, and Pierre Curie, we review early 20th century investigations by Paul Langevin and Pierre Weiss. The Langevin theory of paramagnetism and the Weiss theory of ferromagnetism were partly successful and real understanding of magnetism came with the advent of quantum mechanics. Van Vleck was the pioneer in applying quantum mechanics to the problem of magnetism and we discuss his main contributions: (1) his detailed quantum statistical mechanical study of magnetism of real gases; (2) his pointing out the importance of the crystal fields or ligand fields in the magnetic behavior of iron group salts (the ligand field theory); and (3) his many contributions to the elucidation of exchange interactions in d electron metals. Next, the pioneering contributions (but lesser known) of Dorfman are discussed. Then, in chronological order, the key contributions of Pauli, Heisenberg, and Landau are presented. Finally, we discuss a modern topic of quantum spin liquids. 1 Prologue In this presentation, the development of the conceptual structure of the field is highlighted, and the historical context is somewhat limited in scope. In that way, the presentation is not historically very rigorous. However, it may be useful for gaining a ”bird’s-eye view” of the vast field of magnetism.
    [Show full text]
  • 1972 Frã‰Dã‰Ric and Irãˆne Joliot-Curie
    DISTINGUISHED NUCLEAR PIONEERS—1972 FRÉDÉRIC AND IRÈNE JOLIOT-CURIE The choice of Frédéricand IrèneJoliot-Curie as there under the guidance of his principal teacher, the Distinguished Nuclear Pioneers for 1972 by the So great physicist Paul Langevin, who was the first to ciety of Nuclear Medicine is one of the best that recognize Joliot's exceptional gifts and who had a could be made because their discovery of artificial decisive influence on him, not only in the field of radioactivity was not only a great step forward in science but also in leading him toward socialism and the development of nuclear physics but has also led pacifism. Joliot graduated first in his class, and after directly to the possibility of obtaining radioactive 15 months of military service, he might have started isotopes of practically all the chemical elements— a brilliant career as an engineer in industry. But fol those radioisotopes which are now so widely used lowing the advice of Paul Langevin he became a in medical research or practice, and without which personal assistant to Marie Curie who paid him on nuclear medicine could not exist. a grant from the Rockefeller Foundation. FrédéricJoliot was born in Paris on March 19, Thus Frederic Joliot started his scientific career 1900. His father, Henri Joliot, having participated in in the spring of 1925 at the Institut du Radium of the uprising of the Commune of Paris in 1871, had the University of Paris under the guidance of Marie been obliged to spend several years in Belgium.
    [Show full text]
  • Paul Langevin's 1908 Paper “On the Theory of Brownian Motion”
    Paul Langevin’s 1908 paper “On the Theory of Brownian Motion” [“Sur la théorie du mouvement brownien,” C. R. Acad. Sci. (Paris) 146, 530–533 (1908)] Don S. Lemons and Anthony Gythiel Citation: Am. J. Phys. 65, 1079 (1997); doi: 10.1119/1.18725 View online: http://dx.doi.org/10.1119/1.18725 View Table of Contents: http://ajp.aapt.org/resource/1/AJPIAS/v65/i11 Published by the American Association of Physics Teachers Additional information on Am. J. Phys. Journal Homepage: http://ajp.aapt.org/ Journal Information: http://ajp.aapt.org/about/about_the_journal Top downloads: http://ajp.aapt.org/most_downloaded Information for Authors: http://ajp.dickinson.edu/Contributors/contGenInfo.html Downloaded 16 Apr 2013 to 216.47.136.20. Redistribution subject to AAPT license or copyright; see http://ajp.aapt.org/authors/copyright_permission Paul Langevin’s 1908 paper ‘‘On the Theory of Brownian Motion’’ [‘‘Sur la the´orie du mouvement brownien,’’ C. R. Acad. Sci. (Paris) 146, 530–533 (1908)] introduced by Don S. Lemonsa) Department of Physics, Bethel College, North Newton, Kansas 67117 translated by Anthony Gythiel Department of History, Wichita State University, Wichita, Kansas 67260-0045 ~Received 7 April 1997; accepted 26 May 1997! We present a translation of Paul Langevin’s landmark paper. In it Langevin successfully applied Newtonian dynamics to a Brownian particle and so invented an analytical approach to random processes which has remained useful to this day. © 1997 American Association of Physics Teachers. I. LANGEVIN, EINSTEIN, AND MARKOV in configuration space. This is to say, in modern terminol- PROCESSES ogy, Langevin described the Brownian particle’s velocity as an Ornstein–Uhlenbeck process and its position as the time In 1908, three years after Albert Einstein initiated the integral of its velocity, while Einstein described its position modern study of random processes with his ground breaking as a driftless Wiener process.
    [Show full text]
  • Scientists and War 1916-2016 by Dave Webb Leeds Beckett University and Scientists for Global Responsibility
    Scientists and War 1916-2016 By Dave Webb Leeds Beckett University and Scientists for Global Responsibility The quest for understanding and to know how things work – to find out why they are, what they are - has always been a major driving force for scientists. There are, however, other more negative external drivers – such as the pursuit for military superiority, even in times of peace. Science and engineering have unfortunately made killing easier by helping to develop new types of weapons and World War 1 saw more than its fair share of those. The war also saw a mixture of attitudes from scientists and engineers. Many thought it their duty to help develop new weapons technologies. But there were also those who would not participate in the killing. To understand the social pressures on scientists who spoke out against the war, we need to recognise the cultural context at that time. Just before World War 2 an article in Time magazine dated 11 September 1939, entitled Science and War, expressed the opinion that scientists were not to blame for the way in which their discoveries were used by “men of bad will” and misapplied to “the conquest and murder of men”. This also seemed to be the attitude of many scientists in 1914, and perhaps remains so today. Some though were directly involved. At the outbreak of the First World War, men with specialist scientific and technological skills were not prevented from serving at the Front – by Germany or the Allies. Although some were placed into departments of Time Magazine Front Cover, the armed forces where their skills could be used – for example September 11, 1939 Physicists Ernest Rutherford (Professor of Physics at Manchester since 1907 and winner of the 1908 Nobel Prize in Chemistry) and William Henry Bragg (holder of the Cavendish chair of physics at Leeds since 1909) went to carry out anti-submarine work for the Admiralty.
    [Show full text]
  • Modern Physics
    Modern Physics Luis A. Anchordoqui Department of Physics and Astronomy Lehman College, City University of New York Lesson VIII October 29, 2015 L. A. Anchordoqui (CUNY) Modern Physics 10-29-2015 1 / 26 Table of Contents 1 Origins of Quantum Mechanics Line spectra of atoms Wave-particle duality and uncertainty principle 2 Schrodinger¨ Equation Motivation and derivation L. A. Anchordoqui (CUNY) Modern Physics 10-29-2015 2 / 26 Seated (left to right): Erwin Schrodinger,¨ Irene` Joliot-Curie, Niels Bohr, Abram Ioffe, Marie Curie, Paul Langevin, Owen Willans Richardson, Lord Ernest Rutherford, Theophile´ de Donder, Maurice de Broglie, Louis de Broglie, Lise Meitner, James Chadwick. Standing (left to right): Emile´ Henriot, Francis Perrin, Fred´ eric´ Joliot-Curie, Werner Heisenberg, Hendrik Kramers, Ernst Stahel, Enrico Fermi, Ernest Walton, Paul Dirac, Peter Debye, Francis Mott, Blas Cabrera y Felipe, George Gamow, Walther Bothe, Patrick Blackett, M. Rosenblum, Jacques Errera, Ed. Bauer, Wolfgang Pauli, Jules-mile Verschaffelt, Max Cosyns, E. Herzen, John Douglas Cockcroft, Charles Ellis, Rudolf Peierls, Auguste Piccard, Ernest Lawrence, Leon´ Rosenfeld. (October 1933) L. A. Anchordoqui (CUNY) Modern Physics 10-29-2015 3 / 26 Origins of Quantum Mechanics Line spectra of atoms Balmer-Rydberg-Ritz formula When hydrogen in glass tube is excited by 5, 000 V discharge 4 lines are observed in visible part of emission spectrum red @ 656.3 nm blue-green @ 486.1 nm blue violet @ 434.1 nm violet @ 410.2 nm Explanation + Balmer’s empirical formula l = 364.56 n2/(n2 − 4) nm n = 3, 4, 5, ··· (1) Generalized by Rydberg and Ritz to accommodate newly discovered spectral lines in UV and IR 1 1 1 R − > (2) = 2 2 for n2 n1 l n1 n2 L.
    [Show full text]
  • Paul Langevin and the Theory of Relativity
    Paul Langeyin and the Theory of Relativity Camillo Cuvaj* ... une montee pleine de toumants imprevus et riche de decouvertes, en vue de ce sommet tout enveloppe en brume... Langeyin (1933) I. Introduction—Historical Background Paul Langeyin (1872-1946) is well-known for his exceptional work on magnet ism, but his impressive work on relativity^ has not been sufficiently appreciated. One should not neglect fascinating objects when they are eclipsed by more brillant objects! Lorentz, Poincare and Einstein were historically the main pioneers in special relativity, building the theory to its culmination in 1905. Moreover, other workers participated significantly. Nor did the story end there since theoretical and ex perimental work had to follow: extensions, applications, interpretations and clarifica tion of special relativity—here was the role of Planck, Minkowski and Langevin! The last major contribution to special relativity^ by Einstein was made in 1907, by Poincare in 1906, and Planck in 1908; Minkowski died in 1909 (of appendicitis) and Poincare died in 1912, while in the succeeding decade Lorentz made valuable contributions only on a topic or two. The development of special relativity (starting in 1911) was continued mainly by Langevin, who did essentially the most that was possible in special relativity after * 6047 Palmetto St., Brooklyn, New York 11227, USA. 1 Langevin's collected articles are in his three books: Oeuvres Scientifiques de P. Langevin (Paris: Centre Nat. Rech. Sci., 1950), La Physique depuis vingt ans(Paris: G. Doin, 1923), Izbranye Trudy (Moscow: Izdat. Akad. nauk SSSR, 1960). Bibliographies are in his Oeuvres''' and in La Pensee, mai-juin 1947, 82-87.
    [Show full text]
  • A Brief History of Nuclear Astrophysics
    A BRIEF HISTORY OF NUCLEAR ASTROPHYSICS Stellar Origin of Energy the Elements Nuclear Astrophysics Astrophysics Nuclear Physics A BRIEF HISTORY OF NUCLEAR ASTROPHYSICS PART I THE ENERGY OF STARS Thermodynamics: the age of the Earth and the energy of the Sun 1847 : Robert Julius von Mayer Sun heated by fall of meteors 1854 : Hermann von Helmholtz Gravitational energy of protosolar nebula turns into kinetic energy of meteors Time ~ EGrav/LSun ~ 30 My 1850s : William Thompson (Lord Kelvin) Sun heated at formation from meteorite fall, now « an incadescent liquid mass » cooling age 10 – 100 My 1859: Charles Darwin Origin of species : Rate of erosion of the Weald valley is 1 inch/century or 22 miles wild (X 1100 feet high) in 300 My A gaseous, contracting and heating Sun Mean solar density : ~1.35 g/cc Sun liquid Incompressible 1860s: J. Homer Lane ; 1880s :August Ritter : Sun gaseous Compressible As it shrinks, it releases gravitational energy AND it gets hotter Earth Mayer – Kelvin - Helmholtz Helmholtz - Lane -Ritter A gaseous, contracting and heating Sun Mean solar density : ~1.35 g/cc Sun liquid Incompressible 1860s: J. Homer Lane ; 1880s :August Ritter : Sun gaseous Compressible As it shrinks, it releases gravitational energy AND it gets hotter Earth Mayer – Kelvin - Helmholtz Helmholtz - Lane -Ritter A gaseous, contracting and heating Sun Mean solar density : ~1.35 g/cc Sun liquid Incompressible 1860s: J. Homer Lane ; 1880s :August Ritter : Sun gaseous Compressible As it shrinks, it releases gravitational energy AND it gets hotter Earth Mayer – Kelvin - Helmholtz Helmholtz - Lane -Ritter A gaseous, contracting and heating Sun Mean solar density : ~1.35 g/cc Sun liquid Incompressible 1860s: J.
    [Show full text]
  • Development of Mass Spectrometers from Thomson and Aston to Present
    International Journal of Mass Spectrometry 349–350 (2013) 9–18 Contents lists available at ScienceDirect International Journal of Mass Spectrometry j ournal homepage: www.elsevier.com/locate/ijms Development of mass spectrometers from Thomson and Aston to present a,b,∗ G. Münzenberg a GSI Helmholtzzentrum für Schwerionenforschung, Planckstrasse 1, 64291 Darmstadt, Germany b Manipal University, Manipal 576106, Karnataka, India a r a t i b s c t l e i n f o r a c t Article history: Mass spectrometry contributed to the understanding of the structure of elementary matter including Received 6 February 2013 the isotopic nature of the chemical elements, isotopic abundances, nuclear binding, and the investiga- Received in revised form 7 March 2013 tion of nuclides far-off stability. In this paper the continuous development of mass spectrometers from Accepted 11 March 2013 W. Wien’s first mass analysis to J.J. Thomson’s discovery of isotopes, F.W. Aston’s mass spectrometers, Available online 19 March 2013 and the Mattauch–Herzog double focusing spectrometer to the present rare isotope facilities will be dis- cussed. Separators with magnetic sector fields e.g. from A.O. Nier and the Oak Ridge separator batteries Keywords: for large-scale isotope production are included. The first applications to chemistry and geochemistry will Mass measurements be mentioned briefly. The key role of the development of ion optics from the first geometrical calcula- Sector mass spectrometers tions towards modern matrix method is addressed. Finally recent developments of mass spectrometers Historical developments for basic nuclear research including ISOL and in-flight separators for rare-isotope facilities and mass JEL classification: spectrometry with cooled and stored ions will be presented.
    [Show full text]
  • Magnetic Dipole Field
    Fundamentals of Magnetism Part II Albrecht Jander Oregon State University Real Magnetic Materials, Bulk Properties M-H Loop B-H Loop M B Bs Ms BR MR H H Hci Hc MS - Saturation magnetization Bs - Saturation flux density Hci - Intrinsic coercivity BR - Remanent flux density MR - Remanent magetization Hc - Coercive field, coercivity Note: these two figures each present the same information because B=µo(H+M) Minor Loops M H M M DC demagnetize AC demagnetize H H Effect of Demag. Fields on Hysteresis Loops Measured loop Actual material loop Measured M Measured M Applied H Internal H = 푀 푁푁 Types of Magnetism Diamagnetism – no atomic magnetic moments Paramagnetism – non-interacting atomic moments Ferromagnetism – coupled moments Antiferromagnetism – oppositely coupled moments Ferrimagnetism – oppositely coupled moments of different magnitude Diamagnetism M • Atoms without net magnetic moment H e- H is small and negative Diamagnetic substances: -6 휒 Ag -1.0x10 Atomic number -6 Be -1.8x10 Orbital radius -6 Atomic density Au -2.7x10 -6 H2O* -8.8x10 = 6 2 2 NaCl -14x10-6 푁퐴휌 휇0푍푒 푟 휒 − Bi -170x10-6 푊퐴 푚푒 Graphite -160x10-6 Pyrolitic (┴) -450x10-6 graphite (║) -85x10-6 * E.g. humans, frogs, strawberries, etc. See: http://www.hfml.ru.nl/froglev.html Paramagnetism • Consider a collection of atoms with independent magnetic moments. • Two competing forces: spins try to align to magnetic field but are randomized by thermal motion. H H M µ0mH << kBT µ0mH > kBT colder hotter • Susceptibility is small and positive H • Susceptibility decreases with temperature.
    [Show full text]
  • The Physics of Energy-Gammaitoni
    Corso di Laurea in FISICA The Physics of energy L. Gammaitoni ICT-Energy Summer school 2014, Perugia Corso di Laurea in FISICA IntroducAon to the noon of energy. The energy at the microscopic scale and the entropy Corso di EnergyLaurea in FISICA Energy In physics, energy (Ancient Greek: ἐνέργεια energeia "activity, operation”) is an indirectly observed quantity that is often understood as the ability of a physical system to do work on other physical systems Capability of doing WORK… WORK = FORCE x Displacement "It is important to realize that in physics today, we have no knowledge what energy is." Richard Feynman, in The Feynman Lectures on Physics (1964) Volume I, 4-1 Energy: a hint of history The vis viva (living force), which Goried Leibniz defined as the product of the mass of an object and its velocity squared; he believed that total vis viva was conserved. To account for slowing due to fricAon, Leibniz theorized that thermal energy consisted of the random moon of the constuent parts of maer, a view shared by Isaac Newton, although it would be more than a century unAl this was generally accepted. Energy: a hint of history The conservaon of energy was proposed by Goried Leibniz over the period 1676–1689, the theory was controversial as it seemed to oppose the theory of conservaon of momentum advocated by Sir Isaac Newton and René Descartes. The two theories are now understood to be complementary. In 1807, Thomas Young was possibly the first to use the term "energy" instead of vis viva, in its modern sense.
    [Show full text]